Factors Associated With Exercise Capacity in Patients With Chronic Obstructive Pulmonary Disease

Background: Chronic obstructive pulmonary disease (COPD) is associated with persistent airflow limitation, systemic manifestations, and progressive reduction in exercise capacity, resulting in impaired functional performance and poor clinical outcomes. Exercise intolerance in COPD is multifactorial and influenced by pulmonary dysfunction, skeletal muscle impairment, pulmonary hemodynamic abnormalities, and psychosocial factors. Objective: To determine the clinical, physiological, and psychosocial factors associated with exercise capacity and poor clinical outcomes among patients with chronic obstructive pulmonary disease. Methods: A comparative observational study was conducted among 94 COPD patients, including 47 participants in the intervention group and 47 in the control group. Baseline assessment included demographic characteristics, smoking status, body mass index, forced expiratory volume in one second (FEV1), GOLD stage, six-minute walk distance (6MWD), Borg dyspnea score, and relevant comorbidities. Clinical outcomes assessed during follow-up included change in 6MWD, dyspnea score, quality-of-life improvement, exercise intolerance, COPD exacerbation, hospitalization, and poor clinical outcome. Inferential analysis was performed using odds ratios with 95% confidence intervals. Results: The mean age was 66.4 ± 8.7 years, and 86.2% of participants were male. Mean baseline 6MWD was 431.8 ± 121.6 meters, which improved to 461.7 ± 118.4 meters during follow-up. Baseline 6MWD ≤350 meters significantly predicted poor clinical outcome (OR 2.84, 95% CI 1.15–7.02, p=0.024). Reduced forced vital capacity (OR 2.37, 95% CI 1.01–5.57, p=0.047), quadriceps weakness (OR 3.18, 95% CI 1.29–7.86, p=0.012), pulmonary hypertension or abnormal pulmonary hemodynamics (OR 3.64, 95% CI 1.22–10.89, p=0.021), and low exercise self-efficacy (OR 2.52, 95% CI 1.01–6.31, p=0.048) were also significantly associated with adverse outcomes. Intervention participation demonstrated a protective effect (OR 0.46, 95% CI 0.19–0.98, p=0.041). Conclusion: Exercise capacity impairment in COPD is influenced by multidimensional physiological, muscular, hemodynamic, and psychosocial factors beyond spirometric airflow limitation alone. Comprehensive assessment and targeted rehabilitation strategies may improve functional outcomes and reduce adverse clinical events in COPD patients